Create a Custom Iterator Class in Java for for-in Loop

To create a custom iterator class in Java that can be used with the for-in loop, you need to implement the 'Iterable' interface and provide an implementation of the 'iterator()' method.

Here's an example implementation:

public class MyIterableClass<T> implements Iterable<T> {
    private T[] elements;

    public MyIterableClass(T[] elements) {
        this.elements = elements;
    }

    @Override
    public Iterator<T> iterator() {
        return new MyIterator();
    }

    private class MyIterator implements Iterator<T> {
        private int currentIndex = 0;

        @Override
        public boolean hasNext() {
            return currentIndex < elements.length;
        }

        @Override
        public T next() {
            return elements[currentIndex++];
        }
    }
}

In this example, the 'MyIterableClass' takes an array of elements in its constructor and implements the 'Iterable' interface by providing an implementation of the 'iterator()' method. The 'iterator()' method returns an instance of a private class 'MyIterator' that implements the 'Iterator' interface. The 'MyIterator' class keeps track of the current index and provides implementations of the 'hasNext()' and 'next()' methods.

To use this custom iterator class with a for-in loop, you can simply do:

MyIterableClass<String> iterable = new MyIterableClass<>(new String[]{'hello', 'world'});
for (String element : iterable) {
    System.out.println(element);
}

This will print:

hello
world